Metal working lubricant



United States Patent O No Drawing. Filed Mar. 1, 1965, Ser. No. 436,269 12 Claims. (Cl. 25251.5)

This is a continuation-in-part application of Serial No. 355,419, filed March 27, 1964. i r

This invention relates to metal working lubricants and particularly to non-staining metal working lubricants to avoid discoloration and/or contamination of the metal surfaces.

- Metal working processes, such as cutting, drilling, broaching, rolling, drawing, extrusion, punching and grind-1 ing, require lubricants that'reduce friction and remove heat. Such lubricants must also provide freedom from surface discoloration and/or the formation of carbonaceous surface deposits when the metals are subsequently heat-treated as in annealing operations. Metalsproduced by the recently developed technique of continuously casting require surfaces-free of discoloration and contamination. p

In the cold rolling of hot-rolled ,strip steel to reduce the thickness of the steel strip, a lubricant, usually a mineral oil, is used to lubricate the surfaces of the steel and the rolls. The lubricant, in manycases, serves the dual function of both a lubricant and a coolant. The lubricant can be applied in any suitable manner, such as by brushing or spraying ontothe metal and/or rolls.. Present practice is to apply. the lubricant to the hot-rolled steel strip at the up-coiler after the pickling operation.- The hot-rolled strip is thus provided with lubricant for subsequent cold rolling operations and also an anti-corrosion protective film.

Metal working lubricants for satisfactory reduction of strip steel by cold rolling must provide. good adherence prior to and during the rolling operation, and goodboundary lubrication; should not discolor the cold rolled strip on annealing or leave any residue on the surface which would interfere with further processing; and should be free from objectionable physiological features.

Many types of compounds have been employed as lubricants in the cold rolling of steel strips or sheets but most of them either provide inadequate lubrication or result in an objectionable surface stain or imperfection. Surface appearance of sheet steel has recently become an important economic factor in the uses to which such steel can be placed. Heretofore, mineral oil based lubricants have been used almost exclusively. However, such lubricants suffer the disability of forming objectionable discoloration on the surface of the resulting sheet steel. Also, such mineral oil based lubricants have insuflicient adherency properties to remain on the metal surface after application to the hot-rolled strip steel and prior to cold rolling operations. Further, it was the opinion and belief of those skilled in the steel rolling art that satisfactory boundary lubrication at the rolls could only be achieved with mineral oil lubricants. Attempts to alleviate the deficiencies of mineral oil based lubricants have been unsuccessful. Illustrative of the best heretofore known mineral oil based rolling lubricants is low boiling petroleum distillate containing small amounts of high molecular weight polybutene disclosed in US. 2,256,603. However, elimination of surface discoloration of the steel sheet was not obtainable with this product.

I have discovered that, contrary to the teachings of the art, a superior non-staining metal working lubricant is obtained by the combination consisting essentially of (A) from about 50% to about 98% of liquid polybutenes having a viscosity at 210 F. of from about 30 to about 1100 SSU (Saybolt Seconds Universal); (B) from about ice 2% to about 50% fatty materials which provide lubricity and anti-friction properties to the lubricant; and (C) from about to about of an emulsifier. The polybutenes providethe requisite load bearing properties to the. lubricant. The lubricants of this invention provide the necessary adherence, boundary lubrication, and freedom from surface discoloration and contamination after annealing or casting that is required by various metal workingor fabricating processes.

The liquid polybutenes suitable for use in the present invention are come'rcially available products and can be prepared by polymerizing butenes from a butane-butylene stream as described, for example, in US. Patents 2,407,- 873, and 2,677,000-l-2. The polybutenes have a relatively narow molecular weight range of from about 300 to about 900 molecular weight, are substantially free from vegetable, and marine fats and oils; esters of such fatty acids and 'glycerides; oxidized oils, such as oxidized oil; sulfurized fatty acids and oils, such as sulfurized sperm oil and sulfurized fatty acids; halogenated materials, such as chlorinated paraflin waxes; and naturally occurring and synthetic waxes, such as sperm wax, montan wax, and beeswax. The saturated fatty materials are preferred.

In the following exemplary metal working lubricant formulations, the polybutenes used are identified as: Polybutene A-liquid polybutene having about 300 average molecular weight and a viscosity at 210 F. of about 40 SSU; Polybutene Bliquid polybutene having about 830 average molecular weight and a viscosity at 210 F. of about 1100 SSU; Polybutene Cliquid polybutene having about 460 average molecular weight and a viscosity at 210 F. of about 65 SSU.

Formula 1 Percent Polybutene A 65 Polybutene B 20 Hydrogenated tallow fatty acid 15 Formula 2 Percent Polybutene C 96 Hydrogenated tallow fatty acid 4 Formula 3 Polybutene C 92 Hydrogenated tallow fatty acid 8 Each of the above lubricants was tested on a commercial steel cold rolling mill consisting of four 4-high mill stands 54 inches wide operating at speeds of 800 to 900 feet per minute effecting a reduction in thickness of from about 0.8 to 0.2 inch. The lubricants were applied to the hot-rolled steel strip from the pickling bath as it was being wound into coils on the up-coiler. The hot-rolled coils did not show any corrosion or loss of lubricant from the coils prior to cold rolling. Thereafter, the lubricated coils were passed thru the coldrolling mill without further lubrication; and the rolled strips annealed at about l000-1800 F. After annealing, the annealed sheets did not show any surface discoloration or surface blemishes. Rolling speeds were com parable to the roll speeds obtained with conventionally used mineral oil based lubricants.

In the production of thin tinplate, the previously annealed cold rolled steel sheets are further reduced to the desired thickness. The mechanical energy required to effect this reluction produces substantial heat in the strip. Therefore, water emulsions of the rolling lubricants are used for both lubrication and heat removal. The novel metal working lubricants of this invention can be used to form the desired oil-in-Water emulsions containing from to about 60% lubricant depending on the type of emulsion used by the specific mill. Quick breaking emulsions can be formed without the use of any emulsifier for single use service. For recirculatingtype mills, the addition of up to 5% emulsifier produces a stable emulsion suitable for extended service periods. Conventional emulsifiers for the preparation of oil-inwater emulsions can be used. The preferred emulsifiers are diethanolamine and di'glycolamine. The following formulas illustrate lubricants that form either quick breaking or stable oil-in-water emulsions.

Formula 4 Percent Sperm oil wax Blown sperm oil (Sperm 1000 S) 10 Hydrogenated tallow fatty acid Triethanolamine 5 Polybutene A 60 Formula 5 Percent Sperm oil wax 10 Blown sperm oil (Sperm 1000 S) l0 Hydrogenated tallow fatty acid 15 Polybutene A 65 Formula 6 Percent Sperm oil wax 10 Blown sperm oil (Sperm 1000 S) 10 Hydrogenated tallow fatty acid 15 Diglycolamine 5 Polybutene A u 60 Formula 7 I I Percent Polybutene B 49 Hydrogenated tallow fatty acid 49 Diglycolamine l Oil-in-water emulsions containing from 5% to 60% of the lubricants of Formulas 4-7 were used as the lubricants in the preparation of very thin tinplate from annealed steel strip on a commercial two-stand 4-high mill running at 500 to 900 feet per minute. The mill operated at speeds equivalent to the operating speeds of the mill using conventional mineral oil based emulsions. The tinplate produced had an excellent bright finish, whereas conventional commercial tinplate was slightly discolored, gray and dull in appearance.

The non-staining rolling lubricant of this invention is unique in its ability to reduce the surface discoloration characteristics of mineral oil rolling lubricants. This is illustrated by the following formulations:

Formula 8 Percent Polybutene B Polybutene C 15 Hydrogenated tallow fatty acid 15 Mineral Oil 50 Formula 9 Percent Polybutene C 48 Hydrogenated tallow fatty acid 4 Mineral Oil 48 1 Viscosity 110 SSU at 100 F.

The steel strip rolled with formulations 8 and 9 showed moderate surface discoloration after annealing, whereas the mineral oil lubricant without polybutenes was highly discolored. Thus, the present invention provides a nonstaining cold rolling lubricant that can be used perse, or to form oil-in-water lubricant emulsions, or for improving the non-staining characteristics of mineral oil rolling lubricants.

Sawing of metal stock is a frequently used operation to produce metal shapes and sizes having the desired dimension and configuration. The lubricant used to provide the necessary lubrication and cooling must be easily removed from the metal stock without discoloring the metal or forming undesirable residues. Extrusion is a frequently used technique in the metal fabrication art to form complex forms and shapes. Metal extrusions, such as aluminum, are frequently annealed prior to further fabrication. Conventional metal working lubricants are unsatisfactory saw lubricants because the annealed stock must be recut due to metal discoloration. Consequently, fabrication costs are increased due to unnecessary waste and additional fabrication operations. It has been found that the metal working lubricants of the present invention are very effective lubricants for metal sawing operations. The lubricants are especially effective for metals that must be annealed because they are completely removed during annealing without discoloration of the metal and do not leave any residue. Quite unexpectedly, it has been further found that the lubricants are extremely effective in extending'the saw life, thereby reducing the number of times that the saw must be sharpened. Thus, use of the non-staining metal working lubricants of the present invention permit the fabrication of metal articles at reduced cost because waste is avoided and additional fabricating steps are no longer necessary.

Continuous metal casting processes require non-reactive and residue-free high temperature lubricants. It has been found that lubricants prepared in accordance with this invention are suitable for use in such continuous casting processes; These lubricants having the requisite thermal stability, lubricity, non-reactivity and non-residue forming characteristics consist essentially of the herein defined liquid polybutenes and saturated fatty materials. Exemplary of such lubricants are the Formulas l3 formulations hereinbefore set forth.

The term percent as used herein and in the claims refers to weight percentage.

I claim:

1. A non-staining steel rolling lubricant consisting essentially of from about 50 to about 98% liquid polybutene having a viscosity at 210 F. of from about 30 SSU to about 1100 SSU; from about 2 to about 50% of fatty material which provides lubricity and anti-friction properties to the lubricant; and from 0 to about 5% of an emulsifier.

2. The lubricant of claim 1 wherein said fatty material is hydrogenated tallow fatty acid.

3. The non-staining steel rolling lubricant consisting essentially of a mixture of (A) about 65% liquid polybutene having a viscosity at 210 F. of about 40 SSU; (B) about 20% liquid polybutene having a viscosity at 210 F. of about 1100 SSU; and (C) about 15% hydrogenated tallow fatty acid.

4. The non-staining steel rolling lubricant consisting essentially of about 96% liquid polybutene having a viscosity at 210 F. of about 65 SSU; and about 4% hydrogenated tallow fatty acid.

5. The non-staining steel rolling lubricant consisting essentially of about 92% liquid polybutene having a viscosity at 210 F. of about 65 SSU; and about 8% hydrogenated tallow fatty acid.

6. The non-staining steel rolling lubricant consisting essentially of a mixture of about 60% liquid polybutene having a viscosity at 210 F. of about 40 SSU; about sperm oil wax; about 10% blown sperm oil; about hydrogenated tallow fatty acid; and about 5% triethanolamine.

7. The non-staining steel rolling lubricant consisting essentially of a mixture of about liquid polybutene having a viscosity at 210 F. of about 40 SSU; about 10% sperm oil wax; about 10% blown sperm oil; about 15% hydrogenated tallow fatty acid; and about 5% diglyc-olamine.

8. The non-staining steel rolling lubricant consisting essentially of a mixture of about liquid polybutene having a viscosity at 210 F. of about 40 SSU; about 10% sperm oil wax; about 10% blown sperm oil; and about 15 hydrogenated tallow fatty acid.

9. A water emulsifiable non-staining steel rolling lubricant consisting essentially of (A) about -100% of a mixture of substantially equal parts of liquid polybutene having a viscosity at 210 F. of about 1100 SSU, and hydrogenated tallow fatty acid; and (B) from 0 to about 5% of an emulsifier.

10. The composition of claim 9 wherein said emulsifier is diglycolamine.

11. The non-staining steel rolling lubricant consisting essentially of (A) about 15% liquid polybutene having a viscosity at 210 F. of about 40 SSU; (B) about 20% liquid polybutene having a viscosity at 210 F. of about 1100 SSU; (C) about 50% mineral oil having a viscosity References Cited by the Examiner UNITED STATES PATENTS 2,276,453 3/1942 Bandur 25249.5 2,353,830 7/1944 Kaufman et al. 25249.5 X 2,899,390 8/1959 Plemich 25256 2,974,106 3/1961 Fronmuller et al. 252357 X 3,028,335 4/1962 Shamaiengar 252--49.5 X 3,071,544 1/1963 Rue 25249.5 X

OTHER REFERENCES Ethomeens, Ethomids, Ethofats, product booklet of Armour Chemical Co., Chicago 9, 111. 1949), pp. 2, 3, 21 and 24 most pertinent.

Hydrofol Products, product booklet of Archer- Daniels-Midland 00., Cleveland, Ohio. 1954), pp. 20-29 and 36 most pertinent.

DANIEL E. WYMAN, Primary Examiner.

P. P. GARVIN, Assistant Examiner. 

9. A WATER EMULSIFIABLE NON-STAINING STEEL ROLLING LUBRICANT CONSISTING ESSENTIALLY OF (A) ABOUT 95-100% OF A MIXTURE OF SUBSTANTIALLY EQUAL PARTS OF LIQUID POLYBUTENE HAVING A VISCOSITY AT 210*F. OF ABOUT 1100 SSU, AND HYDROGENATED TALLOW FATTY ACID; AND (B) FROM 0 TO ABOUT 5% OF AN EMULSIFIER.
 10. THE COMPOSITION OF CLAIM 9 WHEREIN SAID EMULSIFIER IS DIGLYCOLAMINE. 